1. Field of the Invention
The invention relates to an apparatus for the deflection of a light beam in two mutually perpendicular directions whereby the deflection in each of the two directions is controllable independently of one another.
2. Description of the Prior Art
Such apparatus comprising a first deflection mirror for the horizontal deflection of the light beam generated by a laser and a second deflection mirror for the vertical deflection of the light beam are, for example, used in the laser scanning of a subject, in processing a workpiece with a laser beam and in particular, in laser labeling. In laser labeling, a photoshutter, the deflection mirrors controllable in accord with the labeling job and a lens which focuses the light beam onto the surface of a part to be labeled are disposed in succession in the beam path of a light beam generated by a laser. With the assistance of such an arrangement, parts of metal, ceramic, semiconductor materials and a multitude of plastics can then be labeled in accord with the labeling job with letters, numerals, marks, company symbols or graphic illustrations, whereby the labeling can be executed in engraving letter in fusing lettering or in evaporation lettering. Galvanometer mirrors having small, very light mirrors are thereby employed as deflection mirrors, these being distinguished by low moments of inertia and a low friction of the movable parts and, thus, allowing a high speed in the laser labeling.
U.S. Pat. No. 3,902,036 appears to show an apparatus for the deflection of a laser beam in two mutually perpendicular directions wherein only a single galvanometer mirror is disposed for the deflection in both directions. In the accompanying description, however, it is expressly emphasized that two galvanometer mirrors are employed in practice and that only one galvanometer mirror was illustrated only for the sake of simplifying the drawing.